1. Field of the Invention
The invention is a new and distinct cultivar known by the varietal name ‘Millbrook’ resulting from the novel hybridization of Salix purpurea with Salix miyabeana. The new variety was produced through controlled willow breeding conducted by the inventors in Syracuse, N.Y. The objective of the breeding program is to produce new willow cultivars that generate high biomass yields on a variety of sites, are resistant to diseases and pests, and possess agronomic traits suitable for mechanical planting, harvesting, and post-harvest processing. Shrub willow is being developed as an agricultural crop plant that will be grown and harvested as a sustainable, renewable source of energy. Once a field planting of shrub willows is established, the woody stems can be harvested every three years, and new shoots will re-sprout the following season. Repeated harvesting every two to four years can be sustained for at least 15 years.
2. Description of Relevant Prior Art Including Information Disclosed Under 37 CFR 1.97-1.99.
This new variety of Salix purpurea×Salix miyabeana was the seedling progeny of the controlled pollination of the female clone Salix purpurea ‘95026’ by the male clone Salix miyabeana ‘SX64’ performed in February 1999 in Syracuse, N.Y. The plant has been propagated repeatedly by stem cuttings and has been found to retain its distinctive characteristics through successive propagations and field trials. More specifically, the plant has been asexually reproduced by collecting dormant stems during winter months, cutting them into either 5 inch or 10 inch pieces (cuttings), then planting those cuttings in the field in the spring or in potting mix in a greenhouse, then transplanting the rooted cuttings to the field.
The female parent, Salix purpurea ‘95026’ was originally identified in 1995 growing on the shore of a creek in Dutchess County, N.Y. and was vegetatively propagated from stem cuttings. This female parent, clone Salix purpurea ‘95026’, is distinguished by opposite leaves that are obovate with entire margins. The variety ‘Millbrook’ has alternate ‘SX64’ was originally transferred from Toronto, Ontario, Canada, to Syracuse, N.Y. in 1994 and was vegetatively propagated from stem cuttings in Syracuse, N.Y. The growth of the parent plants was characterized in nursery plantings. Both parents displayed rapid stem growth and low incidence of disease, so were chosen to serve as parents in a cross. The seedlings produced by this cross (identification #99217) were first established in a greenhouse, and then were transplanted to a field in Syracuse, N.Y. This particular individual (identification #99217-015) was selected from the family due to its exceptional stem height growth.
The new cultivar has been grown in Syracuse, N.Y. and Tully, N.Y., which have a normal yearly average daily temperature of 47° F., normal daily maximum temperature in July of 82° F., normal daily minimum temperature in January of 14° F., and average precipitation of 40 inches. The new cultivar grows from a rooted cutting to a fully mature plant ready for harvest in approximately three years.